Process of tinning sheet-copper



ALFRED A. COWVLES, OF NEW YORK, N. Y.,

PATENT OFFICE.

ASSIGNOR TO THE ANSONIA BRASS AND COPPER COMPANY, OF ANSONIA,CONNECTICUT.

PROCESS OF TINNING SHEET-COPPER.

SPECIFIGATIONforming part of Letters Patent No. 292,540, dated January29, 1884.

Application filed November 9, 1883. -(Xo specimens.)

To all whom it may concern Be it known that I, ALFRED A. COWLES, of thecity and State of New York, have invented an Improvement in the Processof Tin- 5 ning Sheet-Copper, .of which the following is a specification.

Before, my invention sheets of copper had been tinned upon one side bythesheet being pickled and cleaned, after which a flux such as muriateof zino.l'1ad been applied to one surface-of the sheet and the sheet wasplaced in an inclined position and melted tin poured upon the surface ofthe sheet, so as to flow over and adhere to the same. After this thesheet had been wiped. In the tinning operation the heat necessarily madeuse of discolored the, copper surface, rendering it necessary to scourand clean the same. In this operation the smooth and hi ghly finishedsurface resulting from the coldrolling operation was injured. Attemptshave been made to obviate this discoloration by endeavoring to excludethe atmosphere; but the "circumstances under'which the sheet is tinnedrendered it practically impossible.

The nature of my said invention consists in the method of preparing thesheet of copper for the tinning operation, whereby the atmosphere isentirely kept from contact with the side of the copper sheet thatis nottinned, and injury to the surface, either by the action of theatmosphere, the acids, or the tin, is prevented.

In my improved per, after it leaves the finishing-rolls, is subjected tothe usual pickling or cleaning operation for the removal of grease orany substance that might interfere with the tinning operation. I 'thenapply to one surface of the same sheet a coating vhich will not beinjured by the action of t he heating or by the acids employed, andwhich will be easily removed after the tinning has been completed. Iprefer and make use of a liquid silicate of soda as the varnish orcoating for one side of the copper sheet, because this varnish orcoating-is not injured by the heat to which the sheet is subjected; butI do not limit myselfto the use of this coating material, as any othersuitable material having equivalent properties may be made use of. Afterthe said coating becomes sufliciently dry for handling, the

opposite surface of such sheet is prepared in process the sheet ofcopthe ordinary manner for the tinning operation,usually by being rubbedover witha cloth 5 5 or brush saturated with muriate of zinc. Thetinning is then performed, and the surface of such tin wiped off andrendered smooth in the ordinary manner. It is preferable now to immersethe sheet of tinned copper in a bath of boiling water to remove thesilicate of soda or other coating material. This may also be done bybrushing or by rubbing the surface of such copper sheet with a cloth, orwith rollers and hot water, or otherwise, after which the sheet ofcopper is dried and subjected to the ordinary buffing or finishingoperation.

By this process the surface of the copper is not scratched or injured,and there is no discoloration from atmospheric action or from the heatof the table during the operation.

In the ordinary tinning operation the melted tin, or tin and lead it analloy is used, are poured upon the sheet of copper at the high est end,while the sheet rests in an inclined position upon an inclined rack ortable, and the melted tin adheres to the prepared surface, and thesurplus is rubbed off. In my improved process the silicate of soda orother protecting varnish is applied to one surface to protect the same.The sheet is usually warmed and the muriate of zinc rubbed thereon. Thesheets of copper with tin or other coating metal on the surfaces aremuch more perfect than those before made, because the heat does notdiscolor the same, the atmosphere being excluded.

I claim as my invention-- i The process herein specified of tinning, Isheet-copper, consisting in coating one suro face of such copper sheetwith a material that will not be materially injured by the action of theheat made use of, and which will exclude the air, pouring melted tin orother metal over the sheet, allowing the surplus to run off, andspreading the tin or coating metal and rendering the same uniform by arubbing operation, and then removing the protecting-coating from theuntinned side of the copper, substantially as specified.

Signed by me this 3d day of November, A.

' v A. A. COWLES. Witnesses:

G130. T. PINCKNEY, ILLIAM G. Mom.

